The present invention relates to footwear and associated accessories used in snow and ice. In particular, this invention relates to an integrated footwear design and a hardware accessory design that improves the ability to walk on level ground and to climb on steep snow and ice. The invention may be applied to all styles of mountaineering footwear.
Mountaineering boots used to climb tall mountains where one encounters extreme cold temperatures, rock, snow and ice, have always had to compromise between hikeability and climbability. A boot that is ideal for hiking on level or slightly sloped ground where the surface is hard, such as a dirt trail, flexes comfortably at the ball of the foot in consort with the natural hinging of the foot. Such flexing at the metatarsal heads allows the foot to operate in a biomechanically advantageous position throughout the stride because the phalanges can maintain full contact during push-off and the flexor muscles can apply maximum leverage. This is what occurs during normal walking.
A boot that is ideal for climbing has a very rigid sole that does not flex appreciably at the ball of the foot. Rigid soles are important during climbing because they allow the use of rigid crampons with the boots, and because they allow the foot to remain in its most biomechanically advantageous position during climbing. Rigid crampons are generally mounted on the boots as an accessory and require a boot having a rigid sole so that the rigid crampon remains fixed to the boot via the attachment bails at the toe and the heel, and so that flexing of the boot does not put extreme force on the middle of the crampon, where it can be susceptible to breaking. A climber has a biomechanical advantage using a rigid boot having a crampon attached, because the point of contact of the crampon with the earth (ice, snow, or rock) is at the toe tip. A rigid boot allows the foot to apply the maximum force to the toe tip with the minimum muscles strain, thereby making the climber more efficient.
As a consequence of these conflicting performance criteria, high performance boots are suitable to only one type of activity, climbing or hiking. Since most mountains require a flat to moderately sloped approach on foot to the base of the steep and difficult route, climbers must carry two sets of footwear; one for the approach and one for the climb. This is a burdensome requirement in terms of weight and bulk, as well as an expensive one. Although some boots are designed with a medium flex so as to be marginally functional for both activities, professionals and highly skilled climbers cannot accept this compromise in footwear performance. The present invention eliminates the need for two sets of boots without compromising the performance in either hiking or climbing.
This invention is designed to allow footwear to flex comfortably to provide comfortable and efficient hiking performance, and then to be secured in a rigid position with the aid of a unique crampon design, to provide safe and efficient climbing performance. Thus, the same footwear may be used efficiently in the approach to a technical climbing region and, with the addition of an accessory, may be used efficiently and safely in technical climbing activities. The design marries an underfoot frame that provides the proper flex characteristics of the boot as well as the crampon attachment devices, an outsole that is contoured to fit precisely with the crampon, and a unique crampon that attaches to the boot in such a way as to create a rigid system The invention solves the problem of needing to carry two sets of footwear to a mountain and also eliminates the need to compromise the performance of the boots for either hiking or climbing.
The invention comprises three parts: a component that lies under the foot but above the outsole, called the frame, that is integral with the footwear; an outsole that attaches to the bottom of the frame having specialized features for mating with a crampon accessory; and a crampon accessory that can be secured at multiple points to the frame and outsole. The frame and the outsole, which are integral with the footwear, provide the desired flex characteristics for hiking. These characteristics include the ability to flex comfortably across the ball of the foot at the metatarsal heads, and to provide rigidity through the arch and heel, as well as to inhibit twisting of the sole. When the crampon accessory is mounted to the boot using any suitable means, such as a traditional heel lever device, the footwear and crampon accessory system, in combination, becomes rigid and prevents flexing of the footwear at the ball of the foot, even when tremendous force is applied at the toe of the boot. The rigidity of the system stems from the rigidity of the crampon accessory and its attachment at three points of secure contact between the crampon and the boot. When the crampon accessory is positively attached at the toe, heel and at a central location under the foot, preferably at a location between the forefoot and the heel, the crampon""s rigidity prevents the boot from flexing. The rigidity of the footwear and crampon accessory combination is desirably enhanced when the footwear outsole and the crampon accessory additionally interface and, preferably, interlock, at least at one site in proximity to the forefoot.
The frame is preferably constructed as a molded component that extends for the bottom length of the foot and is mounted in a fixed position intermediate the footwear insole and the outsole. The frame provides attachment points for the crampon accessory. In one embodiment, the frame component has a toe lip and a heel lip that extend upwardly from the plane of the footwear sole and provide toe and heel attachment means for mounting a crampon accessory. In another embodiment, the frame component comprises a central attachment means that extends downwardly from the plane of the footwear sole and provides a central attachment means intermediate the toe and heel for mounting a crampon accessory.
The frame component is made from materials and has dimensions that give it the desired flex properties. Specifically, the frame component is preferably made of composite materials or plastics that are strong, yet maintain their physical properties over a wide range of temperatures typically encountered in the high mountains and lowlands of Earth The design and composition of the frame component, and its integration with the footwear, allows the integrated footwear and frame to flex at the ball of the foot when a force, equal to that typically exerted by the human foot during walking, is applied to the forefoot. The frame component is also designed and constructed to inhibit flexing in the arch area or heel due to the dimensions and composition, even when tremendous force is applied to any point of the boot.
The frame component is also equipped with at least two attachment points that cooperate with attachment mechanisms on the crampon accessory to rigidly mount the footwear and crampon accessory to one another. In a preferred embodiment, at least three attachment points are provided on each of the footwear and crampon accessory: one at the toe; one at the heel; and one intermediate the toe and the heel, preferably intermediate the forefoot and the heel, and most preferably in the area under the arch The toe and heel attachment points may be of any conventional design, and may be, for example, of a design similar to those typically found on high performance mountaineering boots. An exemplary toe attachment point on footwear facilitates attachment of a wire bail from the crampon and allows the wire bail from the crampon to wrap around the toe of the boot and to rest securely on top of a flat platform An exemplary heel attachment point on footwear facilitates adjustable attachment of the crampon and cooperates with a plastic or metal heel lever that wraps around the heel of the boot and rests on top of a flat platform.
The third attachment point, intermediate the toe and heel attachment points, anchors the crampon to the sole at a point intermediate the toe and heel attachment points and, preferably, between the forefoot and heel portions, and eliminates movement, particularly flexing, between the boot and the crampon once the crampon is fixed in place. Without the midpoint attachment, a flexible boot may move away from the crampon when force is applied and therefore not perform optimally for climbing. Binding the crampon accessory to the boot at a midpoint as well as the two toe and heel end points, and ensuring that the flex point of the sole is in the forefoot area forward of the intermediate crampon accessory attachment point prevents the footwear from flexing when force is applied downward by a foot.
The outsole of the footwear boot is preferably designed to allow the midfoot crampon attachment in addition to providing for traction and wear protection on various surfaces. The outsole is designed with slots or holes in the area of the intermediate attachment point, preferably in the area under the arch, where the intermediate attachment piece(s) of the frame component protrude from the outer. The outsole is preferably designed to provide a substantial heel portion to provide traction in snow and dirt during ascents and descents.
Additionally, according to a preferred embodiment, a forefoot contact region is provided between the outsole and an accessory device, such as a crampon, to provide enhanced rigidity of the combination in the forefoot region when an accessory is mounted. In one embodiment, the outsole has contact elements that cooperate with stiffening elements formed on the crampon, and that allow the crampon to rest very closely to, or engage, the outsole in the area under the forefoot. This cooperation between rigid stiffening elements of the crampon with mating elements of the outsole in the forefoot area where the outsole has substantial flexibility provides a high degree of rigidity to the outsole when the crampon accessory is installed. The cooperation may be provided by way of one or more mating elements, such as grooves or slots, running lengthwise along the outsole, that cooperate with stiffening rails or tabs on the crampon accessory to mount the crampon accessory and the footwear in a stationary position relative to one another. The mating elements in the outsole, e.g., grooves, allow the crampon to be positioned more closely to the bottom of the boot, reducing the potential for the snow and ice to build underneath the crampon (known as xe2x80x9cballing-upxe2x80x9d), which reduces the effectiveness of the crampons. The mating elements in the outsole also allow the crampon to have a greater contact surface with the sole, thus substantially increasing the rigidity of the system.
The crampon accessory is designed to integrate with the frame component and the footwear outsole and to provide a rigid, integrated footwear/crampon device system. The crampon accessory may be equipped with a wire toe bail for attachment to the frame component (and, hence, the footwear) at the toe, a heel lever for attachment to the footwear at the heel, a midfoot attachment mechanism for attachment to the frame component (and, hence, the footwear) at a location intermediate the toe and the heel, and a rigid forefoot section located intermediate the toe bail and the midfoot attachment mechanism The midfoot attachment mechanism of the crampon accessory cooperates with the midfoot attachment point of the frame component. The crampon is also arrayed with xe2x80x9cpointsxe2x80x9d that are typical of crampon designs, and that provide traction in the ice and snow.
The crampon""s ability to create a rigid system of the crampon/boot combination stems from the way in which the rigid forefoot portion of the crampon bridges the flex zone of the boot and is secured on either side of the flex zone. The frame is designed to flex, not hinge, across the ball of the foot. The frame will bend in an arc with a radius of about 20 mm. This arc represents the flex zone and the midpoint in the arc is referred to as the flex point. By fixing a rigid component (the crampon) to either side of the flex zone (i.e. attaching at the toe and the midpoint of the frame), and by making positive contact with the crampon along cooperating mating elements, such as grooves, in the outsole, the crampon prevents the frame and, hence, the outsole of the footwear, from flexing.
According to one embodiment, the crampon has a hinge in the middle that does not affect the rigidity of the forefoot piece, and allows the crampon to be attached easily to the boot. The hinge may be provided on either side of the midfoot attachment point of the crampon. Multiple hinges or pivots may be provided for ease of installation and removal of the crampon device, provided that the rigidity of the forefoot piece is preserved.